Lubricant and hydraulic fluid composition



Patented Mar. 23., 1948 LUBRICANT AND HYDRAULIC FLUID COMPOSITION Hollis L. Leland, Cranford, N. .L, assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application May 25, 1945, Serial No. 595,883

6 Claims. (01. 252-78) The present invention relates to an improved oil useful as a lubricant, power transmission medium, hydraulic oil, and for other purposes. The specification deals with the oil and its properties as well as method of the manufacture.

For certain uses lubricating oils and hydraulic oils and the like require an unusual combination of properties which, while they may be obtained singly without great difliculty, are extremely difficult to obtain in certain combinations. Hydrocarbon lubricating oils can be obtained with pour points quite loW, for example, 40 F., and in some instances even lower, but such oils are, of course, highly inflammable and at the same time have extremely steep temperature viscosity curves, that is to say, their temperature-viscosity coefficients are very large. For certain purposes it has been very desirable to produce a hydraulic oil, lubricating oil or power transmitting fluid which'has an extremely low pour point so that it can be used in very cold climates, and at the same time to be possessed of a very flat temperature-viscosity curve. Furthermore it would be highly desirable in such an oil to provide a high degree of non-inflammability or at least decrease the flammability so as to reduce the danger of operation. As indicated above, these single properties can be obtained without great difiiculty but it has been found extremely difiicult to obtain fluids possessing all of these properties in combination. Such fluids are particularly valuable for lubricating purposes, hydraulic oils in airplanes, recoil mechanisms and power transmitting devices employing fluid drives, but they are also useful for many other purposes, as will be fully understood.

It has already been suggested that chlorinated aromatic oils may be used as the base or vehicle for such products and they may be thickened and given a flatter viscosity curve by the addition of hydrocarbon polymer thickeners. Heretofore no product which might be said to be highly satisfactory has been produced along these lines. The pour points obtainable are not low enough to be entirely satisfactory andthe viscosity curves are still steeper than desired, at least for the most exacting services. The materials that have been employed as vehicles were the halogenated double ring compounds such as chlorinated diphenyl, chlorinated naphthalene, chlorinated anthracene and the like.

It has now been found that the class of single 4 ring aromatic compounds is considerably superior to the previously used double ring compounds for vehicles in this particular service. Such single ring aromatic compounds can be halogenated, for example, chlorinated, and they should contain from 1 to 5 atoms of halogen per mol of the aromatic compound and should average from about 2.5 to 4.0 atoms per mol. It will be understood that these materials will be mixtures resulting from the direct chlorination of the aromatic hydrocarbon. The compounds which are preferred are not merely the simple ring compounds as represented by benzol but are the alkylated single ring compounds containing at least one side chain of about 2 to 4 carbon atoms such as ethyl, propyl and butyl benzenes. Among all the compounds that have been tried oumene has proved to be the most satisfactory.

To the halogenated product of the type described above, a small amount of a linear polymeric thickener is then added to obtain increase in viscosity and improvement in the shape of the viscosity curve. Materials of this type are represented by polyisobutylene and the polymerized esters of acrylic or methacrylic acids, specifically the esters made from aliphatic alcohols of 2 to 15 carbon atoms. These compounds are known to commerce and preferably those having molecular weights within the range of 1,000 to 15,000 are the grades required for the present material. They are added in a proportion from say 2 to 20%, depending on the degree of thickening required, the oil initially used and the molecular weight of the polymer employed.

While the chlorinated cumene is not completely incombustible, it burns only very slowly and will not support its own combustion. Increasing the amount of the halogen tends to increase the resistance to combustion and also to raise the boiling temperature of the vehicle. In some instances, it has been iounddesirable to add a relatively small amount of very highly chlorinated products such as cai'bon tetrachloride and perchlorethylene, which tend to improve the low temperature characteristics, and at the same time to increase resistance to burning.

Other materials may be added to the present composition for special purposes such as oiliness agents, corrosion inhibitors and the like, and dyes and perfumes may be added if there is particular need in the application contemplated.

In order to more fully understand the present invention, the following examples are given for illustration:

Example 1 Cumene is chlorinated by direct action of chlorine which is bubbled through the liquid at a low temperature, approximately F. in the absence of light with a ferric chloride catalyst in order to introduce the chlorine into the rin instead of the side chain. This is continued so as to obtain a product containing 3.22 atoms of chlorine per mol of cumene. This material is then purified of traces of acidic materials and the first 2 to 5% distillate rejected.

To a sample of this chlorinated product polybutene having a molecular weight of 12,000 was added and gave the following composition:

To this mixture was then added small-quantities of an organic amine inhibitor and an oil:-

soluble metal soap to remove any traces of hydrochloric acid that might be released by hydrolysis.

This material proved to be an excellent low temperature lubricant and power transmission oil. It had a pour point of '80 F. and a suitable-viscosity. The slope of the viscosity-temperature curve was found to be very fiat as seen from the following data:

Centistokes Vis. at 100 F. 36.0 Vis. at 210 F. 11.4

When these data were plotted on the standard A. S. T. M. viscosity chart and the straight line connecting them was drawn, it was observed that the slope was approximately .38, which is unusually flat.

The viscosity data on the chlorinated cumene were as follows: a

' Centistokes Vis. at 100 F. 2.23 Vis. at 210515. .87

The slope of the plot on the A. S. T. M. chart was 1.02.

Example 2 showed the following:

Vis. at 100 F. centistokes 38.6 .Vis. at 210 F ..do 128 Slope of A. S. T. M. curve .38 Pour point F -85 Example 3 For comparison with the above data, there are given the data on a hydrocarbon oil which was made up for similar service and the superiority of the above products canbe readily seen from the following data:

Vis. at 100 F centistokes' 46.8 Vis. at 210 F. do 8.2 A. S. T. M. slope .63

Pour point F --40 I claim:

1. A composition of matter consisting essen- -tially of nuclearly chlorinated cumenes contain,-

ing an average of 2.5 1204.0 atoms of-chlorine per mol of cumene, and 2 to 20% by weight of V alinear organic polymer thickener selectedfrom the group which consists of polymerized isobutylene, acrylic. acid esters, and methacrylic acid esters, said. polymer thickener having a molecular weight within the range of 1,000 to 1 53.000;

' 2. Composition according to claim 1 which contains from 2 to 20% polyisobutylene having a molecular weight between 1,000 and 15,000.

3. Composition according to claim. 1. which contains from: 2 to 20% of a polymerized ester of acrylic acid,

4. Composition according to claim 1 containing from 2 to. 20% of a polymerized ester of methacrylic. acid. 7 i

5. An oil composition consisting essentially of nuclearly chlorinated cumene and 2 to 20% by weight of an organic'linear polymer thickener selected from the group which consists of poly-- merized isobutylene, acrylicv acid esters, and methacrylic acid. esters, said polymer thickener having a molecular weight. within'the range of' 1,000 to 15,000. 2

6. A composition of matter consisting esseni tially of a nuclearly chlorinated single ring aromatic hydrocarbon containing an alkyl side chain of from 2 to 4 carbon atoms, and-2 to 20% by weight of a linear organic polymer thickener selected from the. group which consists of polymerized isobutylene, acrylic acid esters and methacrylic acid esters, said polymer thickener having a molecular weight within the range'of 1,000 to 15,000. r s

V HOLLIS L. LELAND.

REFERENCES CITED The following references are of record: in the file of: this patent: 7

UNITED STATES PATENTS Number V Name I Date; 2,058,899 Matheson Oct. 27, 1936 2,091,627 Bruson- Aug. 31, 1937 2,157,99'1- Brous- May 9 1939. 2,340,946 Ellis Feb. 8, 1944 2,391,092 Horbark Dec. 18, 1945. 2,397,744 Kertesz Apr. 2, 1946 2,413,170 Clark Dec. 24,1946

FOREIGN. PATENTS Number Country Date. 552,056 Great Britain. Mar. 22, 1943 Chem., v01. 32, No. 3,, March 1940, pages 299-304. 

